Optical tapping in an indexing architecture

ABSTRACT

An indexing system includes an indexing component; a redundant optical path; and a fiber tap arrangement. Multiple indexing components can be daisy-chained together in the indexing system. The redundant optical path is created between any forward port and any rearward port in the network. Multiple redundant optical paths can be created within the network. One or more tap arrangements can be disposed along each redundant optical path. Accordingly, feed signals in a bidirectional indexing environment can be supplied to each drop line along the redundant optical path from either direction without recabling.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.16/477,781, filed on Jul. 12, 2019, which is a National StageApplication of PCT/US2018/013329, filed on Jan. 11, 2018, which claimsthe benefit of U.S. Patent Application Ser. No. 62/445,561, filed onJan. 12, 2017, and claims the benefit of U.S. Patent Application Ser.No. 62/558,105, filed on Sep. 13, 2017, the disclosures of which areincorporated herein by reference in their entireties. To the extentappropriate, a claim of priority is made to each of the above disclosedapplications.

BACKGROUND

Passive optical networks are becoming prevalent in part because serviceproviders want to deliver high bandwidth communication capabilities tocustomers. Passive optical networks are a desirable choice fordelivering high-speed communication data because they may not employactive electronic devices, such as amplifiers and repeaters, between acentral office and a subscriber termination. The absence of activeelectronic devices may decrease network complexity and/or cost and mayincrease network reliability.

SUMMARY

Aspects of the present disclosure relate to systems in which opticalsignals are tapped at one or more network nodes.

Some aspects of the disclosure are directed to an example opticalnetwork node including an optical tap, an input line, a first outputline, and a second output line. The optical tap asymmetrically splitsout a first portion of any optical signal received at the input linefrom a remainder of the optical signal. The optical tap splits the firstportion of the optical signal onto the first output line. The opticaltap allows the remainder of the optical signal to pass to the secondoutput line.

The housing supports the optical tap. An input is optically couples tothe input line of the optical tap. A first output optically couples tothe first output line of the optical tap. The first portion of theoptical signal is carried over the first output line, to the firstoutput, and out of the housing without being further split. The secondoutput optically couples to the second output line of the optical tap.The remainder of the optical signal is carried over the second outputline, to the second output, and out of the housing without being furthersplit.

In some implementations, the input includes a de-mateable connectioninterface location. In an example, the de-mateable connection interfacelocation defines a connectorized end of a cable. In another example, thede-mateable connection interface location defines an optical portconfigured to receive a connectorized end of a cable. In certainimplementations, the de-mateable connection interface location isruggedized (i.e., mechanically robust and configured to beenvironmentally sealed). In other implementations, the input includes asplice region disposed within the housing.

In some implementations, the input is accessible from an exterior of thehousing. In other implementations, the input is disposed within aninterior of the housing and is not accessible from an exterior of thehousing.

In some implementations, the first and second outputs include first andsecond de-mateable connection interface locations, respectively. Inexamples, the first and second de-mateable connection interfacelocations define connectorized ends of cables. In examples, the firstand second de-mateable connection interface locations define opticalports configured to receive connectorized ends of cables. In certainimplementations, the de-mateable connection interface locations areruggedized. In other implementations, at least one of the first andsecond outputs includes a splice region disposed within the housing.

In some implementations, one or both of the first and second outputs areaccessible from an exterior of the housing. In other implementations,the first and second outputs are disposed within an interior of thehousing and are not accessible from an exterior of the housing.

In certain implementations, the optical tap is disposed within aninterior of the housing.

In certain implementations, the housing is mounted on a cable spool torotate in unison with the cable spool to dispense an optical cable fromthe cable spool. The optical cable has a first end optically coupled tothe optical tap via the input.

In certain implementations, two or more of the optical network nodes canbe daisy-chained together as part of an optical network. In suchimplementations, the second output of one of the optical network nodesin a chain is optically coupled to the input of a subsequent one of theoptical network nodes.

In an example, optical signals carried over the input line of a firstoptical network node in the chain are split (i.e., power split) at afirst tap so that a portion of the optical signal passes to the firstoutput and a majority of the optical signal passes to the second output.

In certain examples, the optical taps of the optical network nodes areconfigured to split off a common power percentage of the opticalsignals.

In some implementations, the chain of optical network nodes is suitablefor use in a fiber distribution environment inside a building (e.g., amulti-dwelling unit, a shopping mall, an office building, etc.). In somesuch examples, a subscriber line optically couples the first output to asubscriber. For example, the portion of the optical signal tapped ateach optical network node is carried over the first output and over asubscriber line to a room of the multi-dwelling unit, a shop at theshopping mall, or an office of the office building.

In certain implementations, the subscriber line carries the portion ofthe optical signal from the first output to the subscriber withoutfurther splitting the portion of the optical signal.

In certain implementations, a distribution cable is optically coupled tothe first output of an optical network node. The distribution cableleads to an optical splitter disposed at a location spaced from thehousing.

In certain examples, the optical splitter is disposed at a remotelocation from the housing of the optical network node.

In certain examples, the housing includes a first housing piece and asecond housing piece that couple together at a sealing region to sealthe interior of the housing. The sealing region defines cablepass-through locations through which cables enter the interior of thehousing to reach the input cable interface location, the first outputcable interface location, and/or the second output cable interfacelocation.

In certain implementations, an indexing component has a de-mateablefirst multi-fiber connection location, a de-mateable second multi-fiberconnection location, a de-mateable first output connection location, anda de-mateable second output connection location. The indexing componentindexes optical lines between the first and second multi-fiberconnection locations while dropped optical fibers are routed to thefirst and second output connection locations. The first multi-fiberconnection location is configured to receive feed signals in a forwarddirection and the second multi-fiber connection location beingconfigured to receive feed signals in a reverse direction. A redundantfiber path extends between the first output connection location and thesecond output connection location. The optical network node is disposedalong the redundant fiber path.

Other aspects of the disclosure are directed to an optical networkarchitecture including a chain of indexing components. Optical signalscarried along the optical network are dropped in a predetermined patternat the indexing components. One or more tap arrangements are coupled toat least one of the dropped lines to tap off signals from the droppedline. One or more passive optical splitters may split one or more of thetapped signals.

In certain implementations, the indexing components can havehardened/ruggedized connection locations.

In some implementations, the indexing components and tap arrangementsare disposed within a building and configured for indoor use. In otherimplementations, one or more of the indexing components and taparrangements is disposed outdoors and configured for outdoor use.

In some implementations, the optical network supports only singledirection indexing of the optical signals. In other implementations, theoptical network supports bi direction indexing of the optical signals.

Other aspects of the disclosure are directed to an indexed fiber opticnetwork system including a terminal, a redundant fiber path, and a fibertap arrangement. The terminal has a first multi-fiber connectionlocation, a second multi-fiber connection location, a first output port,and a second output port. The terminal includes a first optical fiberextending from the first multi-fiber connection location to the firstoutput port, a second optical fiber extending from the secondmulti-fiber connection location to the second output port, andadditional optical fibers indexed between the first and secondmulti-fiber connection locations. The first multi-fiber connectionlocation is configured to receive feed signals in a forward directionand second multi-fiber connection location is configured to receive feedsignals in a reverse direction. The redundant fiber path extends betweenthe first output port and the second output port. The fiber taparrangement is disposed along the redundant fiber path. The fiber taparrangement includes a first coupler, a second coupler, and a 2×Noptical splitter. The first coupler taps off the feed signal from theredundant fiber path if the feed signal is carried in the firstdirection. The second coupler taps off the feed signal from theredundant fiber path if the feed signal is carried in the seconddirection. The first and second couplers provide any tapped off feedsignals to the 2×N optical splitter.

In certain implementations, the redundant fiber path includes a firstoptical fiber coupled to the first output port and a second opticalfiber coupled to the second output port.

In certain implementations, the first coupler of the fiber taparrangement is disposed along the first optical fiber and the secondcoupler of the fiber tap arrangement is disposed along the secondoptical fiber.

In certain implementations, the redundant fiber path includes a singleoptical fiber.

In certain implementations, the first and second couplers of the fibertap arrangement are disposed along the single optical fiber.

In certain implementations, the fiber tap arrangement is one of aplurality of fiber tap arrangements. Each fiber tap arrangement includesa respective first coupler, a respective second coupler, and arespective 2×N optical splitter. Each first coupler taps off the feedsignal from the redundant fiber path if the feed signal is carried inthe first direction. Each second coupler taps off the feed signal fromthe redundant fiber path if the feed signal is carried in the seconddirection. The first and second couplers provide any tapped off feedsignals to the respective 2×N optical splitters.

In certain implementations, each first coupler is disposed along thefirst optical fiber and each second coupler is disposed along the secondoptical fiber.

In certain implementations, each of the first and second couplers isdisposed along the single optical fiber.

In certain implementations, the first multi-fiber connection locationincludes an input port.

In certain implementations, the first multi-fiber connection locationincludes an input connector terminating a stub cable.

In certain implementations, the second multi-fiber connection locationincludes a port.

In certain implementations, the second multi-fiber connection locationincludes a connector terminating a stub cable.

In certain implementations, the first output port is one of a pluralityof first output ports. Each first output port is configured to receive arespective optical fiber extending from the first multi-fiber cableport.

In certain implementations, the second output port is one of a pluralityof second output ports, each second output port being configured toreceive a respective optical fiber extending from the second multi-fibercable port.

In certain implementations, the terminal is one of a plurality ofterminals. Each terminal has a respective first multi-fiber cable port,a respective second multi-fiber cable port, a respective first outputport, and a respective second output port. Each terminal includes anoptical fiber extending from the first multi-fiber cable port to thefirst output port, another optical fiber extending from the secondmulti-fiber cable port to the second output port, and additional opticalfibers indexed between the respective first and second multi-fiber cableports. The terminals are configured to be daisy-chained together.

Other aspects of the disclosure are directed to a bi-directionalindexing system in which signals supplied from a central office can beselectively routed in a forward or rearward direction. The systemincludes a first terminal, a second terminal, an optical cable, aredundant fiber path, and a tap arrangement. The first terminal has afirst multi-fiber cable port, a second multi-fiber cable port, a firstoutput port, and a second output port. The first terminal includes afirst optical fiber extending from the first multi-fiber cable port tothe first output port, a second optical fiber extending from the secondmulti-fiber cable port to the second output port, and additional opticalfibers indexed between the first and second multi-fiber cable ports.Signals supplied in the forward direction are received at the firstmulti-fiber cable port. The second terminal has a first multi-fibercable port, a second multi-fiber cable port, a first output port, and asecond output port. The second terminal includes a first optical fiberextending from the first multi-fiber cable port to the first outputport, a second optical fiber extending from the second multi-fiber cableport to the second output port, and additional optical fibers indexedbetween the first and second multi-fiber cable ports. The firstmulti-fiber cable port is configured to receive feed signals in aforward direction and second multi-fiber cable port being configured toreceive feed signals in a reverse direction. Signals supplied in therearward direction are received at the second multi-fiber cable port.The optical cable optically couples the second multi-fiber cable port ofthe first terminal to the first multi-fiber cable port of the secondterminal. The redundant fiber path extends between the first output portof the first terminal and the second output port of the second terminal.The fiber tap arrangement is disposed along the redundant fiber path.The fiber tap arrangement includes a first coupler, a second coupler,and a 2×N optical splitter. The first coupler taps off the feed signalfrom the redundant fiber path if the feed signal is carried in the firstdirection. The second coupler taps off the feed signal from theredundant fiber path if the feed signal is carried in the seconddirection. The first and second couplers provide any tapped off feedsignals to the 2×N optical splitter.

In certain implementations, the redundant fiber path includes a firstoptical fiber coupled to the first output port of the first terminal anda second optical fiber coupled to the second output port of the secondterminal.

In certain implementations, the first coupler of the fiber taparrangement is disposed along the first optical fiber and the secondcoupler of the fiber tap arrangement is disposed along the secondoptical fiber.

In certain implementations, the redundant fiber path includes a singleoptical fiber.

In certain implementations, the first and second couplers of the fibertap arrangement are disposed along the single optical fiber.

In certain implementations, the fiber tap arrangement is one of aplurality of fiber tap arrangements. Each fiber tap arrangement includesa respective first coupler, a respective second coupler, and arespective 2×N optical splitter. Each first coupler taps off the feedsignal from the redundant fiber path if the feed signal is carried inthe first direction. Each second coupler taps off the feed signal fromthe redundant fiber path if the feed signal is carried in the seconddirection. The first and second couplers provide any tapped off feedsignals to the respective 2×N optical splitters.

In certain implementations, the first output port of one of the firstand second terminals is one of a plurality of first output ports. Eachfirst output port is configured to receive a respective optical fiberextending from the first multi-fiber cable port.

In certain implementations, the second output port of one of the firstand second terminals is one of a plurality of second output ports. Eachsecond output port is configured to receive a respective optical fiberextending from the second multi-fiber cable port.

A variety of additional inventive aspects will be set forth in thedescription that follows. The inventive aspects can relate to individualfeatures and to combinations of features. It is to be understood thatboth the forgoing general description and the following detaileddescription are exemplary and explanatory only and are not restrictiveof the broad inventive concepts upon which the embodiments disclosedherein are based.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the description, illustrate several aspects of the presentdisclosure. A brief description of the drawings is as follows:

FIG. 1 illustrates an indexing network having a bidirectionalarchitecture;

FIG. 2 illustrates the indexing network of FIG. 1 with a looped cablepathway provided between a forward port and a rearward port of aterminal;

FIG. 3 is an enlarged view of an example implementation of the loopedcable pathway of FIG. 2 including tap arrangements;

FIG. 4 illustrates an example implementation of a tap arrangementsuitable for use with the looped cable pathway of FIG. 3;

FIG. 5 is an enlarged view of another example implementation of thelooped cable pathway of FIG. 2 including tap arrangements;

FIG. 6 illustrates an example implementation of a tap arrangementsuitable for use with the looped cable pathway of FIG. 5;

FIG. 7 illustrates the indexing network of FIG. 1 with a looped cablepathway provided between a forward port of a first terminal and arearward port of a second terminal;

FIG. 8 illustrates an optical network node including an optical tap;

FIG. 9 shows an optical network node mounted on a cable spool to rotatein unison with the cable spool to dispense an optical cable from thecable spool;

FIG. 10 illustrates a chain of optical network nodes suitable for use ina fiber distribution environment, such as a multi-dwelling unit; and

FIG. 11 illustrates an alternative indexing chain environment foroptical network nodes at which an input line, a first output line, and asecond output line are not accessible from an exterior of a housing ofthe node, the first output line being coupled to a remote splittermodule, which further splits the optical signal before the opticalsignals reach the subscribers.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary aspects of the presentdisclosure that are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts.

The present disclosure is directed to uses for optical tapping inoptical networks, including networks having an indexing architecture.For example, optical tapping can be used to provide redundancy to linesdropped off along an indexing network having a bidirectionalarchitecture, can be used to simplify cabling an indexing architecturewithin a multi-dwelling unit, and/or can be used to simplifyinstallation of passive optical networks.

As will be understood by those skilled in the art, the terms “forward”and “rearward” when discussing bidirectional indexing architectures areused for convenience and not meant to be literal. Bidirectional indexingnetworks connect to one or more signal sources at two points (e.g., thenetwork can loop around to the same signal source, opposite ends of thenetwork can connect to different signal sources capable of providing thesame signal, etc.). Forward signals are signals introduced into thenetwork at a first of the points. Rearward signals are signalsintroduced into the network at a different point and able to reach allportions of the network that the forward signals could reach.

FIG. 1 illustrates an example fiber network 100 having an indexingarchitecture. The fiber network 100 includes a signal source 101 (e.g.,a central office, a fiber distribution hub, a headend, etc.) and atleast one indexing component (e.g., terminal or a cable) 110. Eachindexing component 110 includes a first demateable multi-fiberconnection location 111, a second demateable multi-fiber connectionlocation 112, a forward demateable output connection location 113, and arearward demateable output connection location port 114.

Each indexing component 110 may include a housing 115. In some examples,the housing 115 is rigid. In other examples, the housing is flexible. Insome examples, the housing 115 is enterable. In other examples, thehousing 115 has a sealed interior that is not enterable without breakingthe housing 115. In other examples, the indexing component 110 may bedevoid of a housing 115.

Each demateable connection location 111, 112, 113, 114 can include aplug connector, a female connector, or an adapter port configured toreceive a plug connector. Some example plug connectors include ferrulesthat hold one or more optical fibers in a sequence. Other example plugconnectors include ferruleless plug connectors that hold one or moreoptical fibers in a sequence. In certain implementations, eachdemateable connection location 111, 112, 113, 114 can behardened/ruggedized. As the term is used herein, a hardened/ruggedizeddemateable connection location is environmentally sealed and includes atwist to secure fastener (e.g., nuts, threaded couplers, bayonet stylefasteners).

Each demateable output connection location can be either a single-fiberconnection location or a multi-fiber connection location. At least oneoptical fiber extends between the first multi-fiber connection location111 and the forward output connection location 113. At least anotheroptical fiber extends between the second multi-fiber connection location112 and the rearward output connection location 114. Additional opticalfibers are indexed between the first and second multi-fiber connectionlocations 111, 112. Examples of indexing optical fibers betweenmulti-fiber connection locations can be found in U.S. Pat. No.9,348,096, U.S. Publication No. 2015/0378112, U.S. Publication No.2016/0238810, and PCT Publication No. WO 2016/057411, the disclosures ofwhich are hereby incorporated herein by reference.

Distribution cables optically coupled to the forward and rearward outputconnection locations 113, 114 to connect an F2 part of the network 100(e.g., subscribers) to the signal source 101. In some implementations,the distribution cables are single-fiber cables having connectorizedends. In other implementations, one or more of the distribution cablesare multi-fiber cables having connectorized ends. In certainimplementations, the connectorized ends are ruggedized (e.g., areenvironmentally sealed and include a robust twist-to-lock connection).

In some implementations, the first multi-fiber connection location 111includes a multi-fiber port. In other implementations, the firstmulti-fiber connection location 111 includes a multi-fiber connector.For example, the first multi-fiber connection location 111 can bedefined by a multi-fiber connector (e.g., an MPO connector or an HMFOCconnector) terminating a stub cable extending outwardly from a housing115 of the indexing component 110.

In some implementations, the second multi-fiber connection location 112includes a multi-fiber port. In other implementations, the secondmulti-fiber connection location 112 includes a multi-fiber connector.For example, the second multi-fiber connection location 112 can bedefined by a multi-fiber connector (e.g., an MPO connector or an HMFOCconnector) terminating a stub cable extending outwardly from a housing115 of the indexing component 110.

In some implementations, the forward connection location 113 is one of aplurality of forward connection locations 113 of the component 110. Inthe example shown, the indexing component 110 includes three forwardconnection locations 113. In other examples, the component 110 may havea greater or lesser number (e.g., two, four, six, eight, twelve, etc.)of forward connection locations 113.

In some implementations, the rearward connection location 114 is one ofa plurality of rearward connection locations 114 of the component 110.In the example shown, the indexing component 110 includes three rearwardconnection locations 114. In other examples, the component 110 may havea greater or lesser number (e.g., two, four, six, eight, twelve, etc.)of rearward connection locations 114.

In certain implementations, the component 110 has the same number offorward connection locations 113 as rearward connection locations 114.

In certain implementations, multiple indexing components 110 can bedaisy-chained together so that the second multi-fiber connectionlocation 112 of a first component 110 receives the first multi-fiberconnection location 111 of a second component 110. The first multi-fiberconnection location 111 of the first component 110 is optically coupledto the signal source 101; The second multi-fiber connection location 112of the last component 110 in the daisy-chain is optically coupled to thesignal source 101 so that the component 110 are optically connected in aloop with respect to the signal source 101.

The loop can start at signal source 101, extend through the daisy-chainof indexing components 110, and then return to the signal source 101(see fiber line 119 in FIG. 1) to complete the loop. The firstmulti-fiber connection locations 111 of the indexing components 110 canbe referred to as a forward feed connection locations and the secondmulti-fiber connection locations 112 can be referred to as a reversefeed connection location. Signals can be forward-fed from the signalsource 101 to the distribution cables of the F2 portion of the network100 through the first multi-fiber connection locations 111. Signals canbe reverse-fed through the F2 portion of the network 100 through thesecond multi-fiber connection locations 112.

In accordance with some aspects of the disclosure, an optical networkarchitecture includes a chain of indexing components. Optical signalscarried along the optical network are dropped in a predetermined patternat the indexing components. One or more tap arrangements are coupled toat least one of the dropped lines to tap off signals from the droppedline. One or more passive optical splitters may split one or more of thetapped signals.

In certain implementations, the indexing components can havehardened/ruggedized connection locations.

In some implementations, the indexing components and tap arrangementsare disposed within a building and configured for indoor use. In otherimplementations, one or more of the indexing components and taparrangements is disposed outdoors and configured for outdoor use.

In some implementations, the optical network supports only singledirection indexing of the optical signals. In other implementations, theoptical network supports bidirection indexing of the optical signals.

In certain implementations, an indexing component has a demateable firstmulti-fiber connection location, a demateable second multi-fiberconnection location, a demateable first output connection location, anda demateable second output connection location. The indexing componentindexes optical lines between the first and second multi-fiberconnection locations while dropped optical fibers are routed to thefirst and second output connection locations. The first multi-fiberconnection location is configured to receive feed signals in a forwarddirection and the second multi-fiber connection location beingconfigured to receive feed signals in a reverse direction. A redundantfiber path extends between the first output connection location and thesecond output connection location. The optical network node is disposedalong the redundant fiber path.

As shown in FIG. 2, one or more looped cable pathways can be providedalong the indexing network. The looped cable pathways form a loopbetween a forward direction output port and a rearward direction outputport. One or more drop lines can be optically coupled to the indexingnetwork along the looped cable pathway(s). Accordingly, if a breakoccurs in the network 100, the signals can be switched from a forwarddirection to a rearward direction.

For example, a redundant optical pathway 120 can be provided between oneof the forward outputs 113 of the network 100 and one of the rearwardoutputs 114 of the network 100. In some implementations, the redundantpathway 120 can be between forward and rearward outputs 113, 114 of thesame component 110 (see FIG. 2). In other implementations, the redundantpathway 120 can be between forward and rearward outputs 113, 114 ofdifferent indexing components 110 (see FIG. 7).

When the signal source 101 is sending out feed signals in a forwarddirection, the signals are provided to the first multi-fiber connectionlocations 111 of the indexing components 110 and routed to the forwardoutputs 113 of the indexing components 110. Accordingly, the signalswould be carried along the redundant optical pathway 120 from theforward connection location 113. When the signal source 101 is sendingout feed signals in a rearward direction, the signals are provided tothe second multi-fiber connection locations 112 of the indexingcomponents 110 and routed to the rearward outputs 113 of the indexingcomponents 110. Accordingly, the signals would be carried along theredundant optical pathway 120 from the rearward connection location 113.

Referring to FIGS. 2, 3, and 5, one or more tap arrangements 125 aredisposed along the redundant optical pathway 120. Each tap arrangement125 directs a portion of the feed signal to a drop line 130. Each dropline 130 has at least one optical fiber. In certain implementations, thedrop line 130 includes a plurality of optical fibers.

Referring to FIGS. 4 and 6, each tap arrangement 125 includes a firstcoupler 126, a second coupler 127, and a 2×N optical splitter 128. Theoptical splitter 128 receives a first input from the first coupler 126and a second input from the second coupler 127. The optical splitter 128combines the optical signals received over the first and second inputsonto one or more fibers. In the example shown, the optical splitter 128combines the optical signals onto 1 to N optical fibers of a drop line130.

Each of the first and second couplers 126, 127 is configured to tap offsome power from the feed signal carried over the redundant optical path120. In certain implementations, the first and second couplers 126, 127of the same tap arrangement 125 tap off an equal amount of the signal.

In some implementations, each tap arrangement 125 along the redundantoptical pathway 120 taps off the same percentage of the signal from thepathway 120. In such implementations, the same tap arrangement 125 canbe placed at multiple locations along the redundant optical pathway 120.For example, the first coupler 126 of each tap arrangement 125 may tapoff about 5%, about 10%, about 20%, about 25%, etc. of the signalreceived at the first coupler 126. Accordingly, the actual power of thesignal tapped at each subsequent tap arrangement 125 is less than at theprevious tap arrangement 125 (since the signal from which the portion isbeing tapped is weaker).

In certain examples, the percentage to be tapped off may be selected bydetermining the threshold (e.g., minimum) signal strength needed at thefinal tap and selecting a percentage that will result in such thresholdsignal strength at the final tap. In such examples, the signal strengthof the first tap may be significantly more powerful than needed for theapplication.

In other implementations, each tap arrangement 125 along a redundantoptical pathway 120 taps the same amount of power from the signal. Forexample, each first coupler 126 may tap about 5%, about 10%, about 20%,about 25%, etc. of the total power of the signal received at the forwardconnection location 113. To accomplish such a tap, the first couplers126 of a first tap arrangement 125 must tap off a different percentageof the signal from the first coupler 126 of a second tap arrangement125.

In an illustrative example having four tap arrangements, the first taparrangement 125 may tap off about 20% of the signal, the second taparrangement 125 may tap off about 25% of the signal, the third taparrangement 125 may tap off about 33% of the signal, and the fourth taparrangement 125 may tap off about 50% of the signal. In such an example,the same amount of signal power would be tapped off at each taparrangement 125. In other examples, however, the actual percentagesbeing tapped can vary.

Referring now to FIG. 3, in some implementations, the redundant opticalpathway 120 is formed by a first optical fiber 121 and a second opticalfiber 123. The first optical fiber 121 has a first end 122 that isreceived at the forward output 113. The second optical fiber 123 has afirst end 124 that is received at the rearward output 114. Each taparrangement 125 is optically coupled to both the first optical fiber 121and the second optical fiber 123. It is noted that the terms “firstoptical fiber” and “second optical fiber” are not meant to be limited tounbroken lengths of waveguides. Each of the first and second opticalfibers 121, 123 can be formed from multiple optical fibers spliced orconnected together. However, the first and second optical fibers 121,123 are sufficiently separate to form a forward signal pathway and aseparate rearward signal pathway.

FIG. 4 illustrates an example tap arrangement 125 suitable for use withthe first and second optical fibers 121, 123 of FIG. 3. The taparrangement 125 includes a first coupler 126 on the first optical fiber121 and a second coupler 127 on the second optical fiber 123. The firstcoupler 126 taps off a portion of the signal carried in a firstdirection D1 over the first optical fiber 121 and inputs the portion tothe splitter 128. In certain implementations, the first coupler 126 doesnot tap off any signal carried in the second direction D2. The secondcoupler 127 taps off a portion of the signal carried in a seconddirection D2 over the second optical fiber 123 and inputs the portion tothe splitter 128. In certain implementations, the second coupler 127does not tap off any signal carried in the first direction D1.

Referring now to FIG. 5, in some implementations, the redundant opticalpathway 120 is formed by a single optical fiber 121 having a first end122 that is received at the forward output 113 and a second end 122′received at the rearward output 114. It is noted that the term “singleoptical fiber” is not meant to be limiting. The single optical fiber 121can be formed from multiple optical fibers spliced or connectedtogether. However, all fibers along the redundant optical pathway 120are optically coupled such that only one signal path is formed to carryboth forward and rearward signals.

FIG. 6 illustrates another example tap arrangement 125 suitable for usewith the single optical fiber 121 of FIG. 5. The tap arrangement 125includes a first coupler 126 on the single optical fiber 121 and asecond coupler 127 on the single optical fiber 121. The first coupler126 taps off a portion of the signal carried in a first direction D1over the single optical fiber 121 and inputs the portion to the splitter128. In certain implementations, the first coupler 126 does not tap offany signal carried in the second direction D2. The second coupler 127taps off a portion of the signal carried in a second direction D2 overthe single optical fiber 121 and inputs the portion to the splitter 128.In certain implementations, the second coupler 127 does not tap off anysignal carried in the first direction D1.

In certain examples, the splitter 128 is configured to determine whetherthe feed signals are being carried in the first direction D1 or thesecond direction D2. For example, the splitter 128 can includeelectronics that communicate with the signal source 101 or otherwisetrack the direction of the feed signals. The signal 128 can beconfigured to pass on signals only received from the feed signaldirection and to ignore any signals received from the oppositedirection.

While it is preferred for the indexing network disclosed above to have abidirectional architecture, the designs and features disclosed hereinmay have applications to indexing networks with single directionalarchitecture. For example, the tap arrangements can be deployed alongindexing component drop lines to extend the reach of the drop lines in asingle direction indexing environment.

FIG. 8 illustrates an optical network node 200 including an optical tap210. Such an optical network node 200 can be used in various opticalsystems as will be described in more detail herein. For example, certaintypes of optical network nodes 200 are suitable for use as the taparrangements described above.

An example optical network node 200 includes an input line 203, a firstoutput line 205, and a second output line 207. The optical tap 210asymmetrically splits out a first portion (e.g., X%) of any opticalsignal received at the input line 203 from a remainder (e.g., Y%) of theoptical signal. The optical tap 210 splits the first portion of theoptical signal onto the first output line 205. The optical tap 210allows the remainder of the optical signal to pass to the second outputline 207. For example, the optical tap 210 taps X% of the optical poweronto the first output line 205 and directs a remainder of the power ontothe second output line 207.

It is noted that the terms “input” and “output” are used for convenienceand are not intended to be limiting. Optical signals tend to travel inmore than one direction along an optical network (e.g., from a centraloffice to a subscriber and from a subscriber to a central office).Accordingly, optical signals are received at both the designated inputand at the designated output of the node 200. As the terms are usedherein, optical signals received at the input line 203 of the node 200are split onto the output lines 205, 207; optical signals received atthe output lines 205, 207 of the node 200 are joined onto the input line203.

The optical tap 210 is configured so that optical power of the firstportion is less than the optical power of the remainder of the opticalsignal. For example, in various examples, the optical power of the firstportion of the optical signal is less than half the optical power of theremainder of the optical signal. In certain implementations, the opticalpower of the first portion is significantly less than the optical powerof the remainder. In an example, the optical power of the first portionof the optical signal is no more than a third the optical power of theremainder of the optical signal. In an example, the optical power of thefirst portion of the optical signal is no more than a quarter theoptical power of the remainder of the optical signal. In an example, theoptical power of the first portion of the optical signal is no more thana tenth the optical power of the remainder of the optical signal.

A housing 201 of the network node 200 supports or encloses the opticaltap 210. In certain implementations, the optical tap 210 is disposedwithin an interior of the housing 210. In other examples, the housing201 carries the optical tap 210. The housing 201 has an input 202, afirst output 204, and a second output 206. The input 202 is opticallycoupled to the input line 203 of the optical tap 210. The first output204 is optically coupled to the first output line 205 of the optical tap210. The second output 206 is optically coupled to the second outputline 207 of the optical tap 210.

Optical signals received at the input 202 are carried over the inputline 203 to the optical tap 210. The first portion of the optical signalis carried from the optical tap 210, over the first output line 205, tothe first output 204, and out of the housing 201 without being furthersplit. The remainder of the optical signal is carried from the opticaltap 210, over the second output line 207, to the second output cableinterface location 206, and out of the housing 201 without being furthersplit.

In some implementations, the input 202, first output 204, and/or secondoutput 206 are de-mateable connection interfaces (e.g., plug connectorsor optical adapter ports). In other implementations, the input 202,first output 204, and/or second output 206 are glands or other aperturesthrough which a cable can extend. In certain implementations, thedemateable connection interface is ruggedized (i.e., mechanically robustand configured to be environmentally sealed). In other implementations,the input 202, first output 204, and/or second output 206 includes asplice region of the housing 201.

In an example, the input 202 includes a plug connector terminating theinput line 203, which extends out of the housing 201; and the outputs204, 206 include optical ports configured to receive plug connectors. Inanother example, the input 202 and outputs 204, 206 each include opticaladapters having inner ports and outer ports. The inner ports receiveconnectorized ends of the input line 203, first output line 205, andsecond output line 207. The outer ports are configured to receive plugconnectors.

In some implementations, the input 202, the first output 204, and/or thesecond output 206 are accessible from an exterior of the housing 201. Inan example, one or more plug connection ports can be disposed at aperiphery of the housing 201. In an example, one or more connectorizedstub cables can extend through the housing 201 so that the connectorizedends are located outside the housing 201. In other implementations, theinput 202, the first output 204, and/or the second output 206 aredisposed within an interior of the housing 201 and are not accessiblefrom an exterior of the housing 201. For example, the housing 201 caninclude a sealed cable port through which the cables pass so that endsof the cables are disposed within a sealed interior of the housing 201.Within the sealed interior, the cable ends can be spliced or pluggedinto the lines 203, 205, 207 of the optical tap 210.

Referring to FIG. 9, in certain implementations, the housing 201 of theoptical network node 200 is mounted on a cable spool 215 to rotate inunison with the cable spool 215 to dispense an optical cable 220 fromthe cable spool 215. The optical cable 220 has a first end 224 thatoptically couples to the input line 203 of the optical tap 210 (viainput 202). The optical cable 220 has an opposite second end 222 that isdispensed from the spool 215 when pulled. In some examples, the firstend 224 of the cable 220 is optically coupled to the input line 203after paying out the cable 220. In other examples, the first end 224 isoptically coupled to the input line 203 while the cable 220 is beingpaid out from the cable spool 215.

In certain implementations, two or more of the optical network nodes 200can be daisy-chained together as part of an optical network. In suchimplementations, the second output 206 of one of the optical networknodes 200 in a chain is optically coupled to the input 202 of asubsequent one of the optical network nodes 200. Accordingly, opticalsignals carried over the input line 203 of a first optical network node200 in the chain are split (i.e., power split) at a first tap 210 sothat a portion of the optical signal passes to the first output 204 anda majority of the optical signal passes to a subsequent network node 200in the chain via the second output 206 of the first network node 200.

In some examples, the optical taps 210 of the optical network nodes 200are configured to split off a common power percentage of the opticalsignals to the first outputs 204. Accordingly, each output 204 along thechain receives a different amount of power. In other examples, theoptical taps 210 are configured to split off different percentages ofpower so that a common amount of power is supplied to each of the firstoutputs 204 along the chain.

Referring to FIG. 10, in some implementations, the chain of opticalnetwork nodes 200 is suitable for use in a fiber distributionenvironment (e.g., inside a building 250). For example, the chain ofnetwork nodes 200 can be used in a multi-dwelling unit, a shopping mall,an office building, etc. In the example shown, the chain includes afirst optical network node 200A, a second optical network node 200B, anda last optical network node 200N. Additional optical network nodes 200may be supplied between optical network node 200B and optical networknode 200N.

A first optical cable 220A optically couples the first optical networknode 200A to a floor box 230, which is optically coupled to acommunications network. A second optical cable 220B optically couplesthe second optical network node 200B to the first optical network node200A. A Nth optical cable 220N optically couples the Nth optical networknode 200N to the subsequent node in the chain (e.g., the second opticalnetwork node 200B). For example, the second end 222 of each cable 220B .. . 220N is optically connected to the second output 206 of thesubsequent optical network node 200A, 200B. In some examples, each ofthe cables 220A, 220B . . . 220N are deployed from a spool 215 on whichthe corresponding node 200A, 200B . . . 200N are mounted.

In an example, a first of the optical network nodes 200A in the chainhas an input 202 that is optically coupled to a floor box 230. In theexample shown, the input 202 is a connectorized end of the cable 220A.Part of the cable 220A is wound around a spool 215 that carries theoptical network node 200A. The opposite end of the cable 220A isoptically coupled to the input line 203 of the optical tap 210 of thenetwork node 200A. The housing 201 of the optical network node 200Adefines a first output port 204 and a second output port 206 accessiblefrom an exterior of the housing 201.

In some examples, the first output port 204 is a single-fiber outputport. In other examples, however, the first output port 204 can be amulti-fiber output port (e.g., an MPO port, a duplex LC port, an HMFOCport, etc.). In certain examples, the second output port 206 is amulti-fiber output port (e.g., an MPO port, an HMFOC port). In someexamples, the first and second output ports 204, 206 are ruggedizedports. In other examples, the first and second ports 204, 206 are notruggedized ports.

The floor box 230 can be coupled to the communications network via adrop cable, a riser cable, or other optical connection. In someexamples, the building 250 includes multiple floors and each floor mayhave a corresponding floor box 230 coupled to a building distributionpoint (e.g., a fiber distribution hub). Optical signals from a centraloffice of the communications network are supplied to the buildingdistribution point, at which the signals are directed to the floor boxes230. In other examples, the chain can be connected directly to thebuilding distribution point.

In some such examples, a subscriber line 260 optically couples the firstoutput 204 of each node 200A . . . 200N to a subscriber 240 at thebuilding. For example, the portion of the optical signal tapped at eachoptical network node 200 is carried through the first output 204 andover a subscriber line 206 to a room of the multi-dwelling unit, a shopat the shopping mall, an office of the office building, or another typeof subscriber. In certain implementations, the subscriber line carriesthe portion of the optical signal from the first output 204 to thesubscriber 206 without further splitting the portion of the opticalsignal.

In the example shown, a first subscriber line 260A connects a firstsubscriber 240A (shown diagrammatically as an apartment door) to thefirst output 204 of the first network node 200A. A second subscriberline 260B connects a second subscriber 240B to the first output 204 ofthe second network node 200B. An Nth subscriber line 260N connects anNth subscriber 240N to the first output 204 of the Nth network node200N. In some examples, the strength of the signal received by the Nthsubscriber 240N is less than the strength of the signal received by thefirst subscriber 240A. In certain examples, the strength of the signalreceived by each subsequent subscriber 240A-240N in the chain isprogressively less than the strength at the previous subscriber. Instill other examples, each subscriber 240A-240N can receive a signalhaving a common strength.

In some implementations, each subscriber line 260A is routed toequipment disposed at the subscriber 260. For example, each subscriberline 260A can be routed through a wall, door, or window into a roombelonging to the subscriber. The subscriber line 260 can be plugged intoan Optical Network Terminal (ONT) or other equipment in the room.

FIG. 11 illustrates an alternative indexing chain environment foroptical network nodes 200′. Each node 200′ includes an optical tap 210′.At least two optical network nodes 200′ are chained together so that anoptical cable 220B′ optically couples the input line 203 of the opticaltap 210′ of the second node 200B′ to the second output line 207 of theoptical tap 210′ of the first node 200A′. The input line 203 of thefirst node 200A′ is optically coupled to a central office 270 orotherwise coupled to a communications network. The first output line 205of the optical tap 210′ of the first node 200A′ is optically coupled toa cable 260A′ extending out of the housing 201′ of the node 200A′.

In some implementations, the input line 203, first output line 205, andsecond output line 207 are not accessible from an exterior of thehousing 201′ of the node 200A′, 200B′. Rather, cables pass through asealed region 208 (e.g., a gasket, gel, or other sealing mechanism) toan interior of the housing 201′. Within the interior, the cables can bespliced (e.g., see splice region 209), optically connected, or otherwiseoptically coupled to the input line 203, first output line 205, andsecond output line 207.

In certain examples, the housing 201′ includes a first housing piece anda second housing piece that couple together at a sealing region 208 toseal the interior of the housing 201′. The sealing region 208 definescable pass-through locations through which cables enter the interior ofthe housing 201′ to reach the input line 203, the first output line 205,and/or the second output line 207.

In certain implementations, the first output line 205 of an opticalnetwork node 200′ is coupled to a remote splitter module 280, whichfurther splits the optical signal before the optical signals reach thesubscribers 240′. The optical splitter module 280 is disposed at alocation spaced from the housing 201′. In some examples, the splittermodule 280 defines a plurality of output ports at which drop cables 265can be connected. In other examples, the splitter module 280 includespigtail outputs 282 having connectorized ends 283. A connectorized endof a drop cable 265 can be optically coupled (see 269) to theconnectorized end 283 of one of the splitter pigtails 282 to connect asubscriber 240′ to the network.

In certain implementations, the optical signals split by the optical tap210′ at a node 200′ are not split again until reaching the splittermodule 280. Example splitter modules suitable for use with the networknodes 200, 200′ are disclosed in U.S. Pat. No. 7,444,056 and U.S. Pat.No. RE 43,762, the disclosures of which are hereby incorporated hereinby reference. Alternatively, the optical tap 210′ can split the signalsonto multiple fibers of a cable. In such implementations, the cable canbe broken out at as shown in WO 2014/197894 and WO 2014/167447, thedisclosures of which are hereby incorporated herein by reference.

Outputs of the splitter module 280 are directed to subscribers 240′(e.g., via drop cables 265. In certain examples, the drop cables 265 aretether cables having connectorized ends. For example, see U.S. Pat. No.7,744,286, the disclosure of which is hereby incorporated herein byreference. An additional cable 267 can be optically coupled to thetether 265 at a connection point 269. The additional cable 267 can berouted between the tether 265 and the subscriber 240.

Having described the preferred aspects and implementations of thepresent disclosure, modifications and equivalents of the disclosedconcepts may readily occur to one skilled in the art. However, it isintended that such modifications and equivalents be included within thescope of the claims which are appended hereto.

1. (canceled)
 2. An optical network comprising: a plurality of opticalnetwork nodes daisy-chained together, each optical network nodeincluding a housing supporting an optical tap having an input line, afirst output line, and a second output line, the optical tapasymmetrically splitting out a first portion of any optical signalreceived at the input line from a remainder of the optical signal, theoptical tap splitting the first portion of the optical signal onto thefirst output line, the optical tap allowing the remainder of the opticalsignal to pass to the second output line, the first portion being lessthan the remainder, each housing including an input, a first output, anda second output, the input being optically coupled to the input line ofthe optical tap, the first output being optically coupled to the firstoutput line of the optical tap, and the second output being opticallycoupled to the second output line; a distribution cable coupled to thefirst output of a first of the optical network nodes of the chain,wherein the distribution cable receives a first portion of an opticalsignal received at the input of the first optical network node, thefirst portion of the optical signal being carried over the first outputline of the respective optical tap, through the first output, and ontothe distribution cable without being further split; an optical splitterdisposed at a location spaced from the housing of each of the networknodes, the optical splitter being optically coupled to the first outputof one of the optical network nodes in the chain.
 3. The optical networkof claim 2, wherein the housing of the first optical network nodedefines a sealed interior.
 4. The optical network of claim 3, whereinthe housing of the first optical network node includes a first housingpiece and a second housing piece that couple together at a sealingregion to form the sealed interior.
 5. The optical network of claim 4,wherein the sealing region defines a cable pass-through location throughwhich the distribution cable extends into the interior of the housing toreach the first output.
 6. The optical network node of claim 5, whereinthe distribution cable is optically spliced to the first output withinthe interior of the housing.
 7. The optical network of claim 5, whereinthe cable pass-through location enables a first cable to extend into theinterior of the housing to reach the input.
 8. The optical network nodeof claim 6, wherein the first cable is optically spliced to the inputwithin the interior of the housing.
 9. The optical network of claim 5,wherein the cable pass-through location enables a second cable to extendinto the interior of the housing to reach the second output.
 10. Theoptical network node of claim 9, wherein the second cable is opticallyspliced to the second output within the interior of the housing.
 11. Theoptical network of claim 2, wherein the optical taps of the opticalnetwork nodes are configured to split off a common power percentage ofthe optical signals so that an optical power of the first portion of theoptical signal at a first optical network node in the chain is differentthan an optical power of the first portion of the optical signal at asecond optical network node in the chain.
 12. The optical network ofclaim 2, further comprising a subscriber line leading from the firstoutput of another of the optical network nodes in the chain to asubscriber without further splitting any optical signals carried overthe subscriber line.
 13. The optical network of claim 2, wherein theinput line, the first output line, and the second output line of the tapof the first optical network node are not accessible from an exterior ofthe housing.
 14. The optical network of claim 2, wherein the opticalsplitter is disposed within a splitter module, which is disposed at aremote location from the optical network nodes.
 15. The optical networkof claim 14, wherein the splitter module defines a plurality of outputports configured to receive drop cables.
 16. The optical network ofclaim 14, wherein the splitter module defines a plurality of outputpigtails having connectorized ends.
 17. The optical network of claim 16,further comprising a drop cable having a first end optically coupled toone of the output pigtails of the splitter module and a second endoptically coupled to a subscriber.
 18. The optical network of claim 2,wherein the first of the optical network nodes is mounted to a spool.19. The optical network of claim 2, wherein the input defines aconnectorized end of a cable.
 20. The optical network node of claim 2,further comprising: an indexing component having an input, a first droplocation, and a second drop location; and a redundant fiber pathextending between the first and second drop locations of the indexingcomponent; wherein one of the optical network nodes of the chain isdisposed along the redundant fiber path.
 21. The optical network node ofclaim 20, wherein the one of the optical network nodes of the chainreceives input optical signals from both of the first and second droplocations.